Disconnecting switch latch



Oct. 13, 1925- L. B. CHUBBUCK DISCONNECTING SWITCH LATCH Filed July 15, 1920 III!!! I II III II .l

WITNESSES: I I

aamw I INVENTOR Leonard 6. Chubbuc/r ATTORNEY Patented Oct. 13, 1925.

UNITED sT r s Ar ur OFQFICE.

LEONARD B. CHULBBUCK, OF HAMILTON, ONTAB-IO, CANADA, ,ASSIGNO'R T'O WESTING- HOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF YENNSYL- VANIA.

DISCONNECTING- SWITCH LATCH.

Application filed. July 15, 1920. Seria1 No. 396,576.

To all whom 2'25 may concern:

Be it known that I, LEONARD B. Ci-IUB- noon, a subject of the King of Great Britain, and a resident of Hamilton, in the Province of Ontario, Canada, have invented a new and useful Improvement in Disconnecting Switch Latches, of which the following is a specification.

My invention relates to switches and particularly to knife-blade switches such as are employed in connecting the bus bars of a generating station to the service leads or in other high-tension service. Such switches are infrequently operated and are usually devoid of handles, the blades being withdrawn from the contact jaws b v means of a hook-stick or operating tool adapted tobe inserted in holes or recesses in the blades.

It is well known that the electrical stresses incident to the flow of current through the jaws and blades of knife-blade switches tend to move the blades out of engagement with the jaws. Under abnormal or overload conditions, these stresses are frequently sufficient to thrust the switch-blade out of the jaws and thus open the circuit.

Switches of this type are usually provided with latching devices for holding the blades in operative engagement wvith the jaws. Such latching devices are usually designed to be released manually by an operating tool which is usually inserted in a recess in the blade at the moment the switch is to be opened or closed.

One object of my invention is to provide a Switchblade-latching means of simple and durable construction which automatically latches the blade in operative engagement with the jaws when it is moved into closedcircuit position and which may be released by a single withdrawing movement of the operating tool tending to pull the blade out of contact with the jaws.

Another object is to produce a compact latch construction wherein the position of the latch is visible to the operator and wherein the spring employed for maintaining the latch in operative position is of ample proportions and capacity, simple to manufacture and easily assembled and renewed.

These and other objects are attained by means of apparatus embodying the features herein described and illustrated in the drawhereof, wherein: i Fig. 1 is a plan view of a switch embodymg my invention.

Fig. 2 is a side elevation shown in Fig. 1.

Fig. 3 is a side elevation of the end of the blade and a portion of the jaws showing a modified form of latch stop especially adapted for use with the form of latch illusings accompanying and forming a part of the switch trated in Figs. 1. and 2 and upon a blade employed in double-throw switch.

Referring to the drawings, the switchincludes a pair of spaced insulator posts5 and mounted upon a base 7. The post 5-is provided with a jaw member 8 to which a conductor terminal Sis connected. The jaw two pairs of conductor member 8 embodies strips 10 between which the blades lla-re clamped by means of a pivot bolt 12. i

The blades 11 are disposed in spaced relation and are reinforced, intermediate their ends, by means of a block 13 held in place by a rivet 14;. The free ends of theblades are connected by means of a latch stop 15 secured between them and are providedwith aligned perforations or openings "16 into whichthe hook 17 of an operatingrod 18 (shown in Fig. 2') may be inserted.

Upon the post 6 is mounted a contact jaw member 19 comprising two pairs of spaced contact strips 20 disposed in parallel relat-ion so that the spaces between them are;

in the planes of the blades 11 in order to receive the blades when they are moved into circuit-closing position; The contact jaw member 19 is providedwitha terminal I 21 which, for the purpose of illustration, l

may be assumed to be connected to a service lead. The blade 11, therefore, constitutes a connecting link between the terminals 9 and 21. The blade is adapted to be moved into open and into closed position by means of the operating tool 18. In order to maintain the blade in operative engagement with the contact jaws, I provide the jaws with a latch 22 which is pivoted between the pairs of strips 20 upon a shaft 23 extending through the bases of the strips. The latch is provided with a tooth 24 adapted to slip over the ledge 25 on the outer and inner corner of the latch stop 15, when the blade has been moved into operative position, as shown in Fig. 2. The outer end of the latch is rounded at 26 so that it will be forced toward the pivot jaws by engagement with the round inner corner 27 of the stop 15 when the blade is moved into operative engagement with the contact jaws.

In Fig. 3, I have shown a latch stop 15 which is provided with similar oppositely disposed corners or ledges 27, either one of which may serve to retract a latch. This form of stop is especially well adapted for use with a blade of the double-throw type wherein two contact jaw members are employed which are adapted to be separately engaged by the same knife blade. A separate latch'is provided in each contact jaw and is adapted to be retracted by the stop 15.

In the form of switch illustrated in Figs. 1 and 2 a leaf spring 28 is mounted between the pairs of strips 20 and is retained in operative position in contact with the latch 22 by means of a pair of screws 29 which assist in holding the strips 20 in assembled relation and which project into the space between the pairs of jaws. This spring automatically snaps the latch into the position illustrated in Fig. 2 when the blade has been moved to operative'position in the jaws and retains the latch in contact with the blade so as to prevent expulsion of the blade from the jaws.

Vhen it is desired to withdraw the blade from the contact jaws the operating tool is inserted in the opening or recess 16 and moved in a direction tending to move the end of the blade out of the jaws. Movement of the blade is not possible--however, until the latch 22 has been moved to release position, in opposition to the tension of the spring 28. For the purpose of making this action incident to the blade-withdrawing movement of the operating tool, I provide the outer edge of the latch 22 with an upwardly inclined surface 30 which projects across the recess 16 in such manner that the hook of the operating tool may be inserted within the recess beneath the inclined surface. Outward blade-withdrawing movement of the operating tool moves the latch into release position, after which operation the blade is free to be withdrawn from the contact jaws by further movement of the operating tool.

When the blad is moved to closed-circuit position, the corner 27 of the stop 15 first engages the rounded surface 26 of the outer end of the latch and forces the latch aside to permit the entrance of the blade into the aws.

The outward movement of the latch 22 is limited by a stop 31 provided upon the inner end of the latch, adapted to engage the base of the j aws.

\Vhile I have described and illustrated but two embodiments of my invention, it will be apparent to those skilled in the art that various modifications, changes, substitutions, additions and omissions may be made in the apparatus described without departing from the spirit and scope of the invention as set forth in the appended claim.

I claim as my invention:

A switch comprising a pair of blades, a latch stop connecting the blades at one end and disposed between the blades so as to hold them in spaced relation, contact jaws comprising spaced contact members for receiving the blades, the said blades being provided with a recess adjacent the end of the blade into which an operating tool may be inserted for withdrawing the blade from the jaws, a latch pivoted to the jaws and extending between the blades and provided with a tooth for engaging the said latch stop when the blade is moved into operative engagement with the jaws, a spring mounted between the contact members and projecting between said blades and engaging the latch for normally holding the latch in operative engagement with the latch stop, the said latch extending across the recess in the blades and adapted to be engaged by the operating tool and withdrawn from engagement with the latch stop when the rod is moved in a direction tending to withdraw the blade from the jaws.

In testimony whereof, I have hereunto subscribed my name this 28 day of June, 

